# How can siunitx be used with mathematics environment notation?

How can mathematics environment notation be used with units provided by siunitx? Let's way I want to have some code like the following:

\SI{10^{-28}}{m^{2}}


Is it possible to use this mathematics style of notation with siunitx (not the siunitx 10e-28 type of notation)? Is the following a valid alternative?

${10^{-28}}$\,\si{m^{2}}


How could a mathematics style equation be used with siunitx, something like the following?

${a^{b}}$\,\si{m^{2}}

• @JosephWright Hey, thanks for the suggestion. It's a step in the right direction, but when I use code like \SI[parse-numbers=false]{a^{b}}{m^{2}}, I get the mathematics showing in Roman lettering rather than the mathematics lettering. Do you know how to get the mathematics showing correctly? The best I've got remains the ${a^{b}}$\,\si{m^{2}} approach. – d3pd Sep 19 '16 at 9:05
• I'm not sure but maybe there is a misunderstanding going on here? Could it be what you want is simply for the format output to be in the format base^exp? Most likely 10^x? It just seems too strange that you'd want to attach units to arbitrary formulas. Also you forgot to include the second option of Joseph's answer. – Danieru Sep 19 '16 at 20:24

You can turn off the number parse and the 'font control' with something like

\documentclass{article}
\usepackage{siunitx}
\begin{document}

\SI[parse-numbers = false, number-math-rm = \ensuremath]{a^{b}}{\metre}

\end{document}


However, I wonder about the meaning here: it's hard for me to see how you can have a physical quantity expressed in that form!

• The permeability of free space might be a good example. $\mu_0 = 4\pi\times10^{-7}\,\mathrm{H}\,\mathrm{m}^{-1}$ – oliversm Sep 18 '18 at 8:54
• Is it recommended/usual to use siunitx ouside math mode? I always thought all siunitx commands should be wrapped inside . – Minh Nghĩa Oct 17 '20 at 2:32

With the default configuration, just type \SI{e-28}{m^2}:

• Hey, thanks for your answer. What I'm looking to do is specifically to use the standard LaTeX mathematics environment notation with siunitx; that is, I want to use the text 10^{-28} rather than the text e-28. Do you know if this is possible? – d3pd Sep 19 '16 at 8:50
• Unless you hack siunitx, this is not possible. Is there any reason for you to do so? Siunitx is here to avoid the hassle of having to type $10^{-28}\,\mathrm{m}^2$, and it does so in maths mode. – Bernard Sep 19 '16 at 9:20